I would say put a vacuum gauge on it and bump up the timing 2 degrees and see if the vacuum goes up and it idles better. Than take it out and stomp on it. See if it ‘pings ‘. Go from there
The only thing I would add to this is of you do this and you go mash on it and don’t hear any detonation I would still come back and take a close, hard look at the plugs to see if there was any detonation.
It will detonate and show on the plugs before it’s audible.